I pick up my new project in three days. On the test drive, shifting from 2W to 4W, it rolls along fine for a short period ( I think it is still in 2W), then I get a big clunk. It feels like it finally made into 4W after the clunk and rolls down the road jut fine.

It had been sitting for a while before the test drive. There was less of a clunk the second time. No clunk at all the third time. I'm hoping it was just a little stiff from sitting and will never be an issue.

But...anyone with any concerns regarding this mystery clunk in my new clunker? Any advise?

Good new. The front hubs look good, repacked them anyway. All the boots look good. Some surface rust under there, but everything looked strong and stable. Yay!

Bad news. The front still clunks big and bad in 4 wheel drive. Worse is a slow tight turn. Big clunk with each rotation. I'm thinking there is bad news inside one (or more) of those pretty boots. Whether CV or universal ( not sure what's under there yet) but something is upset about sitting all summer.